On the 9th of June 2017, the Hong Kong Census and Statistics Department (C&SD) released the results of its study on household income distribution in the city in 2016. The report outline various important findings such as average household income, employment income and Gini Coefficient. While both the median household income and individual employment income showed positive growth compared to data from 2011 – the Gini Coefficient has reached a new high of 0.539, up by a factor of 0.002 from 0.532 in 2011 – indicating a growing disparity between the rich and the poor.

Used to identify inequality of wealth or income within a nation, the Gini Coefficient is one of the most widely adopted measures of income disparity. Since income disparity is often linked to various socioeconomic impacts, such as individual health and political stability, is the rising Gini Coefficient also indicating a growing health disparity in the society?

Comparing Hong Kong’s Gini Coefficient with other metropolitan cities

In general, the lower the Gini Coefficient, the better with a current worldwide range of 0.24 (Slovenia, lowest) and 0.49 (Chile, highest). When looking at Hong Kong’s Gini Coefficient results, it is clear that there has been a rise in the past five years in regards to original monthly household income; nonetheless, this rise has declined compared to the five years before. Moreover, after discounting the effects of household change and taxation, the Gini Coefficient has actually decreased from 0.421 in 2011 to 0.420 in 2016. When compared to other metropolitan cities such as Los Angeles, New York City and San Francisco, Hong Kong’s raw Gini Coefficient actually falls in-line with the rest of the cities.

Gini Coefficient of Hong Kong and Selected Metropolitan Cities (Source: C&SD)
Gini Coefficient of Hong Kong and Selected Metropolitan Cities (Source: C&SD)

In response to the release of these results, a government spokesman commented that an accelerating ageing population has led to an increase in economically inactive households and subsequently an increased Gini Coefficient.

Can income equality predict individual health status?

While the report emphasises that Gini Coefficient alone cannot reliably predict a nation’s status of inequality – especially without taking into account the socio-demographic status – the question still remains: Can income equality predict individual health status?

A multilevel analysis published by researchers from HKU and Research Office at the Food and Health Bureau in 2008 looked at the health status in comparison to neighbourhood income inequality (based of the Gini Coefficient) and suggested no co-relation between the two. The study surveyed more than 50,000 individuals and found no association between income inequality, median household income or household-level income with an individual’s health status. Ultimately, the study concluded that income quality was not an important predictor of individual health status in Hong Kong.

Meanwhile, another study carried out in the United States found similar results, identifying no clear or implicit link between income inequality and health. On top of reviewing all existing studies relevant to social epidemiology, the study also took a closer look at the modes of measuring income inequality. Means such as distribution of wealth, political power, cultural assets, honorific status and human capital were all regarded as potential determinants of health statuses. Nevertheless, no empirical relation was determined between income inequality and health. The study concluded that Gini Coefficient alone be viewed as indicator of health status without first taking into consideration other factors and developing more sophisticated analytical methods.

What are the other indicators that relate income and health?

If income itself is not a direct indicator of health status, are there any other indicators that relate income and health outcome?

In fact, suicide rates in Hong Kong were found to be closely tied to income and economic status. A study published by researchers from HKU and Taiwan in 2015 looked at the geography of suicide in Hong Kong, and found a distinct geographical distribution of suicides in Hong Kong. Deprived and densely populated areas were found to have increased suicide rates up to 2.3 times higher than in normal areas. Together with income, social fragmentation was another factor associated with increased suicide rates. As such, it was concluded that suicide prevention strategies should consider individuals in low income groups and those living in deprived areas.

Besides income status, WHO has also identified several other factors which are determinants of an individual’s health. These include:

1. Income and social status
2. Education
3. Physical environment
4. Social support networks
5. Genetics
6. Health services
7. Gender

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